Graft copolymers of certain monomeric sulfonic acids on polyvinyl lactams, improved acrylonitrile polymer compositions obtainable therewith, and method of preparation



March 20, 1962 s. A. MURDOCK ETAL 3,02

GRAFT COPOLYMERS OF CERTAIN MONOMERIC SULFONIC ACIDS ON POLYVINYL LACTAMS, IMPROVED ACRYLONITRILE POLYMER COMPOSITIONS OBTAINABLE THEREWITH, AND METHOD OF PREPARATION Filed Nov. 25, 1957 FILAMENTOUS ARTICLE COMPRISED OF AN ACRYLONITRILE POLYMER HAVING A GRAFT C0- POLYMER OF A MONOMERIC ORGANIC SULFONIC ACID GRAFT COPOLYMERIZED UPON A VINYL LACTAM POLYMER INCORPORATED THEREIN.

IN V EN TORS.

STANLEY A. MURDOCK TEDDY G. TRAYLOR United States Patent w 3,026,291 GRAFT COPOLYMERS OF CERTAIN MONGMERIC SULFONIC ACIDS ON POLYVINYL LACTAMS, IMPROVED ACRYLONITRILE POLYMER COM- POSITIONS OBTAINABLE THEREWITH, AND METHOD OF PREPARATION Stanley A. Murdock and Teddy G. Traylor, Concord,

Calii, assignors to The Dow Chemical Company, Midland, MielL, a corporation of Delaware Filed Nov. 25, 1957, Ser. No. 693,740 17 Claims. (Cl. 260-455) The present invention resides in the general field of organic chemistry and contributes specifically to the polymer art, especially with respect to graft copolymer compositions and fiber-forming polymer blends obtainable therewith. lt is particularly concerned with graft copolymers of certain monomeric sulfonic acids on polyvinyl lactams that have especial utility as dye-receptive, antistatic and stabilizing additaments for acrylonitrile polymer compositions which, advantageously, may be of the fiber-forming variety. The invention is also concerned with the compositions that may be obtained by blending the graft copolymers with acrylonitrile polymers, as well as with shaped articles which have been fabricated from such compositions and which as a consequence, have significantly enhanced properties and characteristics as regards improvements in and relating to enhanced dye-receptivity, minimized inherent propensity to accumulate electrostatic charges, natural stability to various deteriorating influences, including stability against becoming deleteriously influenced and degraded upon exposure to heat at elevated temperatures and to light. Within the scope and purview of the invention, there is comprehended (l) the novel and utile graft copolymers of the indicated variety; (2) the advantageous polymer compositions, particularly fiberforming compositions, obtained by blending the graft copolymers with acrylonitrile polymers; (3) various shaped articles fabricated from and comprised of the graft copolymer-containing acrylonitrile polymer compositions; and (4) methods for the preparation of the above-indicated compositions.

It is the main purpose and primary design of the present invention to provide and make available graft copolymers of certain monomeric sulfonic acids on vinyl lactam polymers that are especially well suited for being incorporated in acrylonitrile polymer compositions, particularly compositions of polyacrylonitrile, to serve in the indicated treble capacity of dye-assisting adjuvants, antistatic agents and stabilizing ingredients. It is also a principal aim and chief concern of the invention to provide and make available acrylonitrile polymer compositions and shaped articles therefrom that contain the above-indicated and hereinafter more fully delineated type of graft copolymeric additaments which compositions have, as intrinsic distinguishing characteristics, excellent receptivity of and acceptability for any of a wide variety of dyestuffs; permanently imbued antistatic properties that are unusually good for and not commonly encountered in polymeric materials of the synthetic, essentially hydrophobic varieties of such substances; and efiicacious natural stability to heat and light, as well as to certain chemical conditions, such as alkaline environments.

The graft copolymers of the present invention which have the indicated capacity and utility as additaments for acrylonitrile polymer compositions are comprised of a (b) polyvinyllactam trunk or base on which there is graft copolymerized a (a) monomeric, vinyl or other alkenyl group-containing, organic sulfonic acid or derivative thereof that is selected from the group of such 3,026,291 Patented Mar. 20, 1962 compounds (including mixtures thereof) consisting of those represented by the formulae (aromatic organic sulfonic acid compounds) CH =CH(CH SO X (alkenyl organic sulfonic acid compounds) (snlfoalkylacrylate organic sulfonic acid compounds) z ('allyl taurine homolog compounds) all wherein X is hydrogen, an aliphatic hydrocarbon radical containing from 1 to 4 carbon atoms or an alkali metal ion (including sodium, potassium and lithium); Y is hydrogen, chlorine or bromine; R is methyl or ethyl; Z is hydrogen or methyl; m has a numerical value in whole number increments from 0 to 2; n has a numerical value of 1 or 2; p is 0 or 1 and r is l to 4.

The polymer blend compositions of the present invention which fulfill the above-indicated ends and offer corollary advantages and benefits, particularly as fiber-forming compositions as will hereinafter be manifest, are, in essence, comprised of an intimate and practically inseparable blend or alloy constitution of (A) an acrylonitrile polymer that contains in the polymer molecule at least about percent by weight of polymerized acrylonitrile which, preferably, is of the fiber-forming variety and, most advantageously, is polyacrylonitrile and (B) a minor proportion of the above-indicated variety of beneficial graft copolymeric additament that functions in the described manner.

The methods of the invention by Which the herein contemplated advantageous compositions may be made involve preparation of the graft copolymer, as well as incorporation of a minor proportion of the graft copolymer product as a beneficial additament in and with the acrylonitrile polymer base by any of several beneficial techniques, hereinafter more thoroughly defined, adapted to suitably accomplish the desired result.

Without being limited to or by the specific embodimerits and modes of operation set forth, the invention is illustrated in and by the following didactic examples wherein, unless otherwise indicated, all parts and percentages are to be taken on a weight basis.

EXAMPLE A Into a 5 liter reactor that was equipped with an eflicient agitator, a nitrogen sparger, and a total reflux condenser, there was charged about 370 grams of 47.36 percent aqueous solution of polyvinylpyrrolidone (PVP) having a Fikentscher K-value of about 52. About 800 milliliters of water was added to the PVP solution. The resulting aqueous solution was brought to the boil and nitrogen was then sparged into the reactor. The nitrogen sparging was conducted throughout the ensuing reaction. Over a three hour period, about grams of a sodium styrene sulfonate monomer dissolved in Water to a total volume of 2,000 ml. and 0.3 gram of hydrogen peroxide dissolved in Water to a total volume of 500 ml. were continuously pumped into the reactor. The sodium styrene sulfonate monomer was about 41.6 percent active as determined by bromination. The balance of the styrene sulfonate was substantially all sodium bromide with a small quantity of sodium sulfate and a trace of polymer in the monomeric material. After the entire quantities of the monomer and catalyst solutions had been charged to the reactor, the heating was continued and the temperature of the reaction mass was maintained at about 98 C. for an additional one hour period. The reaction was then terminated and the graft copolymer-containing solution was removed from the reactor. The polymer product was a clear, light brown solution that had a polymer content of about 7.8 percent. Upon analysis, it was observed that about 95 percent of the sodium styrene sulfonate monomer had been converted to a graft copolymer product with the PVP.

Polyacrylonitrile fibers containing about percent of the above copolymer product were prepared by impregnating filamentary structures that were in aquagel condition (after having been salt-spun and wet-stretched) in and with a dissolved aqueous solution of the copolymer that contained about 3 percent (graft) copolymer solids. The polyacrylonitrile aquagel fiber that was employed had been obtained by extruding a spinning solution of fiber-forming polyacrylonitrile comprised of about 10 parts of the polymer dissolved in 90 parts of a 60 percent aqueous solution of zinc chloride through a spinnerette having 750 individual 6 mil diameter orifices into an aqueous coagulating bath that contained about 42 percent of dissolved zinc chloride to form a multiple filament tow. After being spun, the tow bundle of coagulated polyacrylonitrile aquagel fiber was washed substantially free from salt upon being withdrawn from the coagulating bath and then wet-stretched for orientation to a total stretched length that was about thirteen times its original extruded length. The aquagel fiber was then passed through the mentioned aqueous impregnating bath of the dissolved copolymer additive so as to become impregnated therewith to the indicated extent. The impregnating bath was maintained at the boil and Was simultaneously employed as a hot stretching medium for the aquagel fiber.

Following the impregnation, the aquagel fiber was irreversibly dried at 150 C. to destroy the water-hydrated structure and convert it to a finished fiber form. It was then heat set for five minutes at 150 C. The finally obtained 3 denier fiber product had a tenacity of about 4.0 grams per denier, an elongation of about 29 percent, and a wet yield strength of about 0.9 gram per denier. The copolymer-containing acrylonitrile polymer fiber product was found to have excellent natural stability to heat and light as well as against becoming degraded under the influence of aqueous alkaline media at pH levels as high as 10. It was found to be nearly free of propensity to accumulate charges of static electricity uponh-andling; being about commensurate at about 60 percent relative humidity with viscose rayon fibers in this regard. As widely appreciated, viscose rayon is not considered to be afllicted to a troublesome degree with problems due tostatic.

In addition, the graft copolymer-containing sample had good color and hand and was dyeable with all classes of dyestuffs as applied under normal dyeing conditions.

The fiber product dyed well to deep and level shades of coloration with Calcodur Pink 2BL, a direct type of dyestufi (Colour Index Direct Red 75, formerly Colour Index 353) and Sevron Brilliant Red 4G, a basic dye formerly known as Basic Red 46 (Colour Index Basic Red 14).

The dyeing with Calcodur Pink 2BL was performed at the 4 percent level according to conventional procedure in whichthe 'fiber sample was maintained for about one hour at the boil in the dye bath which contained the dyestuif in an amount equal to about 4 percent of the weight of the fiber. The dyebath also contained sodium sulfate in an amount equal to about 15 percent of the weight of the fiber and had a bath-to-fiber weight ratio of about 30: 1, respectively. After being dyed, the fiber was rinsed thoroughly with water and dried for about 20 minutes at C. The dye-receptivity of the Calcodur Pink 2BL-dyed fiber was then evaluated spectrophotometrically by measuring the amount of monochromatic light having a wave length of about 520 millimicrons from a standard source that was reflected from the dyed sample. A numerical value on an arbitrarily designated scale from zero to one hundred was thereby obtained. This value represented the relative comparison of the amount of light that was reflected from a standard white tile reflector that had a reflectance value of 316 by extrapolation from the 0-100 scale. Lower reflectance values are an indication of better dye-receptivity in the fiber. For example, a reflectance value of about 20 or 25 to 50 or so for acrylonitrile polymer fibers dyed with 4 percent Calcodur Pink 2BL is generally considered by those skilled in the art to be representative of a degree of dye-receptivity that readily meets or exceeds the most rigorous practical requirements and is ordinarily assured of receiving general commercial acceptance and approval. The 4 percent Calcodur Pink 2BL reflectance value of the copolymer-containing fiber product was about 27.

The antistatic properties of the copolymer-containing fiber were then determined by measuring the electrical conductance of the fiber product at various humidities. As is also appreciated by those who are skilled in the art, the basis for such a test is that all fibers have a tendency to generate static electricity upon being handled. Only those that are possessed of suflicient electrical conductance to dissipate the charge as quickly as it forms are not hampered by the bothersome eflfects of electricity. Thus, a measure of the electrical conductance of a fiber is a good indication of its ability to dissipate static electricity. The conductivities of the various fiber samples tested were found by determining their electrical resistances. Resistance, of course, is the reciprocal quantity of conductivity. In order to permit various fiber samples to be compared on a common basis, the conductivities of the samples tested were actually measured as volume resistivities according to the following formula:

Volume resistivity The units of volume resistivity are ohm-cmP/cm.

Prior to being tested, the graft copolymer-containing polyacrylonitrile fiber prepared in the indicated manner was vat dyed in the conventional manner with Cibanone Green BF Dbl. Paste (Color Index Vat Green No. 1). A portion of the vat dyed sample was then subjected to fifteen (15) consecutive No. 3-A accelerated wash tests in accordance with the American Association of Textile Chemists and Colorists (AATCC) Manual. The actual resistivities of the merely vat dyed sample as well as that of the sample that had been both vat dyed and wash tested were then determined (after the samples being tested were conditioned for seventy-two hours at the particular tem-- perature and relative humidity conditions involved in each of the tests) by tautly connecting a web-like sample of the yarn between two electrodes, each of which were 9 centimeters long spaced parallel 13 centimeters apart, and across which there was applied a 900 volt direct current potential. For purposes of comparison, the volume resistivities of cotton, wool and an unmodified polyacrylonitrile fiber (obtained in the same way as the copolymercontaining fiber but Without having the polymeric additament incorporated therein) were also tested in the indiaceaem cated manner along with the graft copolymer-containing fiber in accordance with the present invention.

The results are set forth in the following tabulation which indicates the volume resistivities obtained at various relative humidities (RH) at 23 C. of each of the samples tested.

Table l.V0lume Resistivities of Various Fiber Samples Compared to Polyacrylanitrile Fibers Impregnated With Graft Copolymer of Sodium Styrene Sulfonate on PVP As is apparent in the foregoing, the graft copolymer-containing sample, even after being severely washed, had electrical conductance properties much superior to ordinary polyacrylonitrile and only slightly poorer than cotton. At the same time, the physical properties of the copolymercontaining fiber were excellent, being about equal to those of the unmodified polyacrylonitrile fiber.

In contrast with the foregoing, a polyacrylonitrile fiber prepared in the above-indicated manner so as to be impregnated while in the aquagel form with a mere physical mixture of PVP and the homopolymer of sodium styrene sulfonate produced a fiber which had a very harsh feeling and an undesirable hand. When this fiber sample which contained the mere physical mixture of PVP and the sodium styrene sulfonate homopolymer is subjected to severe washing and vat dyed in general accordance with the fore going procedure, its volume resistivity characteristics and static properties are about the same upon testing as those indicated in the above table for unmodified polyacrylonitrile.

EXAMPLE B Using the same apparatus as described in Example A, about 1000 grams of a percent aqueous solution of PVP having a Fikentscher K-value of about was charged to the reactor. brought to the boil, at which point nitrogen sparging was commenced and continued throughout the entire run. About 460 grams of 50 percent active sodium styrene sulfonate monomer, dissolved in Water to a total volume of about 2670 ml., and 0.1 gram of hydrogen peroxide, dissolved in water to a total volume of 272 ml., were continuously metered into the hot PVP solution in the reactor over a 3 hour period. After the addition of the aqueous solutions of monomer and catalyst had been completed, the charge in the reactor was held at the boil for about 2 hours. At the termination of the polymerization reaction which occurred, the graft copolymer-conraining reaction mass was drained and a clear, light brown polymer solution was obtained. The conversion of monomer to graft polymer was found to be about 56 percent. The product solution was found to contain about 14 percent of dissolved graft copolymer solids in which the ratio of PVP to sodium styrene sulfonate graft copolymerized thereon was found to be on the order of 7l.6:28.4, respectively.

A solution of about 3 percent of the graft copolymer was prepared to impregnate a polyacrylonitrile aquagel fiber in a manner similar to that set forth in Example A. The impregnation of the copolymeric additament was accomplished during the stretch drawing of the aquagel in the second stage of the physical extension operation by The PVP solution was then means of which the fiber was being oriented and while it was immersed in the hot graft copolymer solution. The total stretching of the aquagel was performed in a four stage operation. In the first stage, the aquagel was cold stretched with a stretch ratio of 1.56:1. The initial cold stretching was followed by three hot stretch stages (the first of which being the above-mentioned stage in which the impregnation was accomplished) wherein the sequential stretches imposed were on the order of 3.89 times; 1.89 times; and 1.20 times their initial length prior to stretching, respectively. After being impregnated with the copolymer, the aquagel fiber was dried at about C. It was found to contain about 3.5 percent of the polymeric additament intimately incorporated therein.

The graft copolymer-containing fiber had good color, excellent hand and was dyeable with all classes of dyes at normal dyeing conditions. and alkaline media having a pH as high as 10 were excellent. Its physical properties were as follows:

Denier 3.1 Tenacity grams per denier 2.5 Elongation percent 29 Dry yield strength grams per denier 0.83 Wet yield strength "do-.." 0.56

The volume resistivities under various conditions of relative humidity at 23 C. of the graft copolymer-containing fiber product were determined in the manner set forth in Example A after a portion of the fiber had been vat dyed with Cibanone Green BF, Dbl. Paste and a portion of the vat dyed fiber subjected to five (5) No. 3A accelerated wash tests. The values found for the vat dyed fiber were l.6 l() ohrn-cm. /cm. at 47 percent RH and 8.4 -10" ohm-cm. /cm. at 66 percent RH. The values for the vat dyed and wash tested sample were 1.4 l0 ohm-crn. cm. at 47 percent RH and 12x10 ohm-cm. cm. at 66 percent RH. The superiority in antistatic properties of the graft copolymer-containing fiber, even after severe scouring, dyeing and washing treatments, is evidenced by comparison of the foregoing volume resistivity values with those obtained under the same conditions for cotton, wool and unmodified polyacrylonitrile fibers as set forth in the preceding Table 1.

EXAMPLE C The general procedure of the foregoing examples was employed to prepare a graft copolymer from the following charge which was polymerized for about 16 hours at a temperature of 50 C.:

The aqueous solution of the raft copolymer that was obtained as a product was clear and only slightly colored. Conversion of the monomer to graft copolymer was found to be about 87.3 percent. The graft copolymcr product contained about 54 percent PVP and 46 percent graft copolymerized sodium vinyl benzyl sulfonate. It was found to be an excellent dye additive and permanent antistatic agent for acrylonitrile polymer fibers when it was incorporated in them in the manner set forth in the preceding examples. The fibers had good dye-receptivity, excellent static character istics, satisfactory stability and suitable physical properties.

EXAMPLE D Following the procedure of Example C, graft copolymer products were obtained'from each of the following charges:

BATCH D-l Acryloyl taurine, sodium salt grams 1.1 PVP (Filientscher K-value of 57) do 2.6 Water ml 15.2

Its stability to light, heat graft copolymer-containing- 7 Potassium persulfate grams 0.02 pH of charge 7.5 Conversion of monomer to graft copolymer percent 88.8

The product was a slightly colored solution. It contained a graft copolymer of about 72 percent PVP upon which there was graft copolymerized about 28 percent of the taurine. The nomenclature taurine, incidentally, is commonly employed to designate Z-aminoethane sulfonic The dissolved graft copolymer solution that was obtained as a product had a slight yellow coloration. The composition was about 72 percent PVP and 28 percent graft copolymerized sodium Z-sulfoethyl acrylate.

BATCH D-3 2-sulfoethyl methacrylate, sodium salt grams- 1.1 PVP (Fikentscher Kvalue of 57) do 2.6 Water ml 15.2 Potassium persulfate "grams" 0.02 pH of charge 8.5

Conversion of monomer to graft copolymer percent 90.5

The product graft copolymer solution had a slight yellow color. The composition of the graft copolymer was about 72 percent PVP and 28 percent graft copolyrnerized sodium 2-sulfoethyl methacrylate.

Excellent results commensurate with those set forth in the first three examples, were obtained when each of the above graft copolymer products were incorporated in polyacrylonitrile fibers following the procedure set forth in the first example. Excellent results were also obtained when the foregoing general procedure was repeated to prepare graft copolymers upon PVP of allyl taurine; sodium salt; graft copolymers upon PV? of allyl propene sulfonic acid; and graft copolymers upon PVP of the sodium salt of ethylene sulfonic acid with each of the graft copolymer products having compositions equivalent to those described.

Excellent results may also be obtained when the foregoing is repeated to prepare graft copolymer additives from poly-N-vinylcaprolactarn, poly-N-vinyl--methyl-2- pyrrolidone, poly-N-vinylpiperidone and other vinyl lactam polymers. Results similar to those set forth in the foregoing can likewise be obtained when the graft copolymer additaments are incorporated in polyacrylonitrile and other acrylonitrile polymer fibers to provide articles in accordance with the present invention by blending the graft copolymer and the fiber-containing acrylonitrile polymer in a spinning composition or dope prior to its extrusion into filamentary products by either wet spinning or dry spinning techniques. In such instances, incidentally, it may be desirable, in order tosecure optimum benefit in the practice of the invention, to employ relatively larger quantities of the graft copolymeric additament than when surface impregnation is performed so that the presence of effective quantities of the additament at or near the peripheral portion of the article is assured.

' Besides those specifically illustrated herein, other organic sulfonic acids and derivatives may also be utilized for the preparation of the water-insoluble .copolymers of the present invention such, by way of illustration, as those which are set forth in the disclosure of United States Letters Patent Number 2,527,300. In addition to the copolymers specifically described in the foregoing examples, other Water-insoluble copolymeric additaments that may advantageously be employed in the practice of the present invention include copolymers of such organic sulfonic acids and derivative monomers as 2-propene sulfonic acid; sodium para-vinylbenzene sulfonate; 2- and/or 3-sulfopropyl acrylate; a-sulfoacrylic acid; sodium vinyl toluene sulfonate; potassium ortho-chlorostyrene sulfonate; 2-hydroxy-3-sulfopropyl acrylate, sodium salt; sodium 3-allcxyl-Z-hydroxypropane sulfonate; 4-sulfophenyl acrylate, sodium salt; N-allyl imino di-(2-ethane sulfonic acid); and the like, on a (b vinyl lactam polymer, including in particular polyvinyl pyrrolidone (PVP) and polyvinyl caprol'actam. 7

Still other organic sulfonic acids and derivative monomeric sulfonic acid compounds that may be employed are as set forth in the following representative, but by no means exhaustive, listing wherein they are grouped according to the above designated types.

Aromatic alkenyl group-containing sulfonic acid compounds (Formula I):

Para-styrene sulfonic acid Ortho-styrene sulfonic acid Para-isopropenyl benzene sulfonic acid Para-vinylbenzyl sulfonic acid Ortho-isopropenyl benzyl sulfonic acid Sodium para-styrene sulfonate Potassium ortho-styrene sulfonate Methyl para-styrene sulfonate Ethyl para-vinylbenzyl sulfonate Ortho-vinyl benzyl sulfonic acid Isopropyl ortho-isopropenyl benzene sulfonate n-Butyl ortho-styrene sulfonate Tertiary butyl para-styrene sulfonate 2-chloro-4-vinyl benzene sulfonic acid 4-bromo-2-isopropenyl benzene sulfonic acid 3-vinyl toluene 6-sulfonic acid, sodium salt 2-ethyl-4-viuyl-benzene sulfonic acid 2,3-dichloro-4-vinyl benzene sulfonic acid 2,3,5-tribromo-4-vinyl benzene sulfonic acid 2-chloro-3-vinyl toluene-G-sulfonic acid 2,3-diethyl-4-vinyl-benzyl sulfonate, sodium salt 0 Alkenyl sulfonic acid compounds (Formula II):

Ethylene sulfonic acid Sodium ethylene sulfonate Potassium ethylene sulfonate Methyl ethylene sulfonate Isopropyl ethylene sulfonate l-propene S-Sulfonic acid l-propene l-sulfonic acid, sodium salt l-propene 2-sulfonic acid, ethyl ester l-butylene 4-sulfonic acid, n-butyl ester l butylene 3-sulfonic acid Tertiary butylene sulfonic acid Sulfoalkylacrylate compounds (Formula III):

Sulfomethylacrylate 2-sulfoethylacrylate Sulfornethylmethacrylate, sodium salt Z-sulfoethylmethacrylate, methyl ester 2-sulfoethylmethacrylate, potassium salt a Acryloyl taurine and homologous compounds (Formula IV) N-acryloyl taurine N-acryloyl taurine, sodium salt N-methacryloyl taurine, methyl ester N-methacryloyl taurine, potassium salt N-acryloyl taurine, ethyl ester 7 N-acryloyl-aminomethane sulfonic acid N-methacryloyl-aminomethane sulfonic acid, sodium salt Methyl N-methacryloyl-aminomethane sulfonate Allyl taurine and homologous compounds (Formula V):

Allyl taurine Allyl taurine, sodium salt Allyl taurine, potassium salt Methallyl taurine Methallyl taurine, methyl ester Methallyl taurine, isopropyl ester N-allyl-aminomethane sulfonic acid Sodium N-allyl-aminomethane sulfonate Lithium N-methallyl-aminomethane sulfonate n-Butyl N-allyl-aminomethane sulfonate The vinyl lactam polymers that are utilized in the preparation of the graft copolymeric additaments of the pres ent invention may be any of those (or their mixtures) which are variously characterized and generically known to the art as poly-N-vinyl lactams or poly-l-vinyl lactams. Such polymers as have been described or which may be prepared from the mentioned varieties of monomers that are involved in U.S. Patents Nos. 2,265,450; 2,317,804; and 2,335,454 may be suitably employed in the practice of the invention. Advantageously, without intending any limitation, the poly-N-vinyl lactam that is used for the manufacture of the graft copolymer may be one having a molecular weight between about 3.8x 10 and 2.8x 10 as evidenced by a Fikentscher K-value between about and 55. Beneficially, as has been indicated, the poly-N- vinyl lactams that are employed are poly-N-vinyl-pyrroli done or poly-N-vinylcaprolactam, particularly the former.

The graft copolymers of the present invention may generally be prepared by methods of polymerization, such as those which have been demonstrated in the foregoing illustrative examples, that employ such polymerization catalysts as persulfates, organic and inorganic peroxide and azo type materials in quantities that are conventional for such uses. The graft copolymers may oftentimes be prepared by polymerizing the monomeric constituent onto the vinyl lactarn polymer under the influence of high energy irradiation such as by means of X-rays and the like, or simply by heating or evaporating the monomer-containing polymerization mixture. The graft copolymers may be prepared in both aqueous and organic solvent vehicles using temperatures for the desired polymerization that may vary from about room temperature to the boiling point of the polymerization mixture. It is ordinarily satisfactory to conduct the reaction at a temperature of about 50 to 80 or 100 C. Usually, depending on the specific factors that may be involved, the graft copolymerization may be accomplished satisfactorily within a time period of about 5 to 60 hours.

The compositions of the graft copolymer can vary within rather wide limits. The content of the monomeric constituent that is graft copolymerized on the vinyl lactam polymer may advantageously be between about 10 and 80 percent by weight of the resulting graft copolymer product and, more advantageously, between about and 60 weight percent. In many cases, especially to secure optimum dye-receptivity, nearly equivalent or about commensurate or equal weight proportions of the vinyl lactam polymer and the monomeric constituent graft copolymerized thereto may be employed with benefit in the practice of the graft copolymeric additaments.

The polymerization system that is employed for the preparation of the graft copolymers of the present invention may consist of as much as 50 percent by weight of the mixture of monomers and vinyl lactam polymers to be polymerized in the aqueous or other medium. The amount of polymerizable constituents that are provided in the graft copolymerization system may be influenced somewhat by the manner in which it is intended to incorporate the roduct in the synthetic polymer compositions in order to provide the graft copolymer-containing acrylonitrile polymer compositions of the invention.

If, for example, it is intended to incorporate the graft copolymer products by blending into a fiber-forming composition prior to its fabrication into shaped articles, the polymerization system may, if desired, contain about equal proportions by weight of the charged polymerizing constituents and the polymerization medium which, preferably, is miscible with and tolerable in the spinning solution solvent intended to be used. In such cases, the graft copolymer product may ordinarily be readily isolated from unreacted monomer and directly incorporated in the fiber-forming composition. If the incorporation of the graft copolymer in a fiber-forming composition is to be achieved by impregnation therewith of an alreadyformed shaped article of the composition, it may be desirable to effect the graft copolymerization so as to directly form a suitable applicating solution (or suspension in the cases where a non-solvent polymerization Vehicle is employed) of the graft copolymer product. For such purposes, the polymerization system may be prepared to contain as little as 2 or 10 percent by weight of the polymerizing monomeric and polymeric ingredients. Such a method for preparing the graft copolymers may be especially appropriate when they are intended, in the practice of the present invention, to be applied to acrylonitrile polymer fibers and the like that are derived from aqnagels in the course of their manufacture, such as the acrylonitrile polymer fibers that are wet spun from aqueous saline solutions of the fiber-forming polymer.

In such instances, as has been demonstrated, the graft copolymeric additament may be impregnated into the fiber from aqueous solution While the fiber is in a swollen or gel condition, as a polyacrylonitrile fiber in an aquagel condition, in order to obtain the desired copolymer-containing product.

If desired, the copolymer-containing acrylonitrile polymer compositions may comprise as much as 20 or more percent by weight of the graft copolymeric additament, based on the weight of the composition. Usually, however, suitable properties and characteristics and better fiber-forming properties in a given composition may be achieved when lesser proportions of the copolymeric additament are incorporated therein. An appreciable improvement in dye-receptivity, antistatic properties and stability may frequently be obtained when a quantity of the copolymeric additament that is as small as 2 (and even as low as l or less) percent by weight is employed. Advantageously, an amount between about 6 and 12 percent by weight of the copolymeric additament may thus be utilized in the composition. Greater advantages may often accrue when the amount of the copolymeric additarnent that is incorporated in the composition is in the neighborhood of 5-10 percent by weight, based on the weight of the composition.

As has been indicated, the copolymeric additaments may be incorporated in the acrylonitrile polymer compositions according to various techniques. Thus, for example, the copolymeric additament and the acrylonitrile polymer may be directly blended in order to provide the composition which, incidentally, may be used for any desired fabrication purpose in addition to fiber-forming and the like. Beneficially, when insoluble polymers are involved, the polymers may be comminuted, either separately or in combination, before being intimately blended together by mechanical or other means. The blended polymers may be prepared into suitable fiber-forming systems by dissolving or otherwise dispersing them in a suitable liquid medium. Or, the compositions may be provided in fiber-forming system by sequentially dispersing the polymers in any desired order in a suitable medium, as by incorporating the copolymeric additament in a prepared acrylonitrile polymer spinning solution, dope or the like.

As is evident from the illustrative examples heretofore included, a highly advantageous technique for providing the compositions, particularly when acrylonitrile polymer fiber products are involved, is to apply or impregnate the copolymeric additament from an aqueous dispersion thereof to a shaped acrylonitrile polymer article that is in an aquagel condition in a manner similar and analogous to that employed for the impregnation of vinyl lactam polymers as described in the disclosure contained in the copending application of George W. Stanton, Theodore B. Lefierdink, Richard W. Meikle and Mary J. Charlesworth for a Method and Composition for Rendering Polyacrylonitrile Readily Dyeable having Serial No. 333,385 which was filed on January 26, 1953, now abandoned. Thus, an acrylonitrile polymer filamentary article that has been spun from an aqueous saline spinning solution may be conveniently passed, after its coagulation and while it is in an aquagel condition, through a water bath containing the dissolved graft copolymeric additament in order to impregnate the filament with the graft copolymer and provide a composition and an article in accordance with the invention. In addition, as has been demonstrated in the examples, in situ polymerization techniques may also be relied upon to provide the copolymeric additament in the acrylonitrile polymers in either fabricated or unfabricated form.

The compositions of the invention may advantageously be utilized in or with fiber-forming systems of any desired type in order to provide fibers and the like according to procedures and techniques that are conventionally employed for such purposes in the preparation of fibers and such related shaped articles as filaments, strands, yarns, tows, threads, cords and other funicular structures, ribbons, tapes, films, foils, sheets and the like which may be manufactured from synthetic polymeric materials. It is frequently desirable to employ concentrated solutions of salts or mixtures of salts as the dispersing or dissolving media for such purposes. Such solution may, a has been indicated, contain at least about 55 percent by weight, based on the weight of the solution, of zinc chloride or other known saline solvents for the polymer. Acrylonitrile polymer fiber products that are spun from saline fiber-forming systems may, by way of further illustration, be coagulated in more dilute saline solutions of a like or similar nature and may then be processed after coagulation according to conventional techniques of washing, stretching, drying, finishing and the like with the modification of the present invention being accomplished prior or subsequent to the spinning as may be desired and suitable in particular instances.

The acrylonitrile polymer fiber products in accordance with the present invention (one of which is schematically illustrated in the sole figure of the accompanying drawing) have excellent physical properties and other desirable characteristics for a textile material and have a high capacity for and are readily and satisfactorily dyeable to deep and level shades with any of a wide variety of dyestufls. For example, they may be easily and successfully dyed according to conventional procedures using acid, vat, acetate, direct, naphthol, basic and sulfur dyes. Such dyestuffs, by way of didactic illustration, as Calcocid Alizarine Violet (Colour Index 61710, formerly Colour Index 1080), Sulfanthrene Red 3B (Colour Index Vat Violet 2), Amacel Scarlet GB (Colour Index 11110 also known as Amacel Scarlet BS, and having American Prototype Number 244), Calcodur Pink 2BL (Colour Index 353, also more recently, Colour Index Direct Red 75), Naphthol ASMX (Colour Index 35527), Fast Red TRN Salt (Colour Index Azoic Diazo Component 11), and Immedial Bordeaux G (Colour Index Sulfur Brown 12) may advantageously be employed for such purposes.

Other dyestuffs, by way of further illustration, that may be utilized beneficially on the graft copolymer-containing, polymer blended fiber products of the invention include such direct cotton dyes as Chlorantine Fast Green 5BLL (Colour Index Direct Green 27), Chlorantine Fast Red 73 (Colour Index Direct Red 81), Pontamine Green GX Gene. 125 percent (Colour Index Direct Green 6), Calcomine Black EXN Conc. (Colour Index Direct Black 38), Niagara Blue NR (Colour Index Direct Blue 151) and Erie Fast Scarlet 4BA (Colour Index Direct Red 24); such acid dyes as Anthraquinone Green GN (Colour Index Acid Green 25), Sulfonine Brown 2R (Colour Index Acid Orange 51), Sulfonine Yellow 26 (Colour Index Acid Yellow 40), Xylene Milling Black 23 (Colour Index Acid Black 26A), Xylene Milling Blue FF (Colour Index Acid Blue 61), Xylene Fast Rubine 3GP PAT (Colour Index Acid Red 57), Calcocid Navy Blue R Conc. (Colour Index Acid Blue 120), Calcocid Fast Blue BL (Colour Index Fast Blue 59), Calcocid Milling Red 3R (Colour Index Acid Red 151), Alizarine Levelling Blue 2R (Colour Index Acid Blue 51), Amacid Azo Yellow G Extra (Colour Index Acid Yellow 63) such mordant-acid dyes as Alizarine Light Green GS (Colour Index Acid Green 25); such basic dyes as Brilliant Green Crystals (Colour Index Basic Green 1) and Rhodamine B Extra S (Colour Index Vat Blue 35); such vat dyestufis as Midland Vat Blue R Powder (Colour Index Vat Blue 35), Sulfanthrene Brown G Paste (Colour Index Vat Brown 5), Sulfanthrene Blue 2B Dbl. paste (Colour Index Vat Blue 5 and sulfanthrene Red 3B paste (Colour Index Vat Violet 2); various soluble vat dyestufis; such acetate dyes as Celliton Fast Brown BRA Extra CF (Colour Index Dispersed Red 13), Artisil Direct Red SBP and Celanthrene Red 3BN Conc. (Both Colour Index Dispersed Red 15), Celanthrene Pure Blue BRS 400 percent (Colour Index Dispersed Blue 1) and Acetamine Yellow N (Colour Index Dispersed Yellow 32); B-Naphthol 2-chloro-4-nitroaniline, an azoic dye; such sulfur dyes as Katigen Brilliant Blue GGS High Conc. (Colour Index Sulf. Blue 9) and Indo Carbon CLGS (Colour Index Sulf. Blue 6); and various premetallized dyestulfs.

The dyed products are generally lightfast and stable to heat and are well imbued with a good resistance to crocking. In addition, the dyed products exhibit good wash fastness and retain the dye-assisting copolymeric additament in a substantially permanent manner, despite re peated exposure and subjection to washing, laundering and dry cleaning treatments.

What is claimed is:

1. Graft copolymer comprising between about 10 and percent by weight of (a) at leact one alkenyl groupcontaining organic sulfonic acid compound selected from the group consisting of those represented by the formulae:

UHF? (CHEM-$03K CHFCH-(CH2)mSO X (II all wherein X is selected from the group consisting of hydrogen, saturated aliphatic hydrocarbon radicals containing from 1 to 4 carbon atoms and alkali metals; Y is selected from the group consisting of hydrogen, chlorine and bromine; R is selected from the group consisting of methyl and ethyl; Z is selected from the group consisting of hydrogen and methyl, m is an integer from 0 to 2; n is an integer from 1 to 2; p is an integer from 0 to l, and r is an integer from 1 to 4; and (b) from to 20 percent by weight of a vinyl lactam polymer.

2. The graft copolymer of claim 1, containing in the polymer molecule between about 30 and 60 percent by weight of said organic sulfonic acid compound graft copolymerized with the Vinyl lactam polymer.

3. The graft copolymer of claim 1, wherein said vinyl lactam polymer with which the organic sulfonic acid (clompound is graft copolymerized is poly-N-vinylpyrrolione.

4. Method for the preparation of a graft copolymer which comprises polymerizing between about 10 and 80 percent by weight, based on the Weight of the resulting graft copolymer, of at least one alkenyl group-containing organic sulfonic acid compound selected from the group consisting of those having the formulae:

UHF? (CH2)p-SO3X CHFC H(C H2) -SOaX (ID CHFfiI-C O O-(CHz) n-SOzX CHFO-C ONE-(CH1) n-SOIX i av) CHFC-CH2NH(CH2) n-SOsX i on all wherein X is selected from the group consisting of hydrogen, saturated aliphatichydrocarbon radicals containing from 1 to 4 carbon atoms and alkali metals; Y is selected from the group consisting of hydrogen, chlorine and bromine; R is selected from the group consisting of methyl and ethyl; Z is selected from the group consisting of hydrogen and methyl, m is an integer from to 2; n is an integer from 1 to 2; p is an integer from 0 to l; and r is an integer from 1 to 4; with between about 90 and 20 percent by weight of a vinyl lactam polymer.

5. Composition comprising a major proportion of (A) a fiber forming polymer of an ethylenically unsaturated monomeric material containing at least about 80 percent by weight of acrylonitrile and (B) a minor proportion of up to about 20 percent by weight, based on the weight of the composition, of a graft copolymer of (a) between about and 80 weight percent of at least one alkenyl group-containing organic sulfonic acid compound selected from the group consisting of those having the formulae:

all wherein X is selected from the group consisting of hydrogen, saturated aliphatic hydrocarbon radicals containing from 1 to 4 carbon atoms and alkali metals; Y is selected from the group consisting of hydrogen, chlorine and bromine; R is selected from the group consisting of methyl and ethyl; Z is selected from the group consisting of hydrogen and methyl, m is an integer from O to 2; n is an integer from 1 to 2; p is an integer from 0 to l; and

r is an integer from 1 to 4; and (b) from about 90 to 20 weight percent of a vinyl lactam polymer.

6. The composition of claim 5 containing between about 6 and 12 percent by weight, based on the weight of the composition, of said graft copolymeric additament.

7. The composition of claim 5, wherein said graft copolymer contains between about 30 and 60 percent by weight of said organic sulfonic acid compound graft copolymerized with said vinyl lactam polymer.

8. The composition of claim 5, wherein component (B) is a graft copolymer of sodium styrene sulfonate with poly-N-vinylpyrrolidone.

9. The composition of claim 5, wherein component '(B) is a graft copolymer of sodium-Z-sulfo ethyl meth-; acrylate with poly-N-vinylpyrrolidone.

10. The composition of claim 5, wherein component (B) is a graft copolymer of sodium vinyl benzyl sulfonate with poly-N-vinylpyrrolidone.

11. The composition of claim 5, wherein component (B) is a graft copolymer of acryloyl taurine, sodium salt with poly-N-vinylpyrrolidone.

12. The composition of claim 5, wherein component (B) is a graft copolymer of 2-sulfo propyl acrylate, SOdi-t um salt with poly-N-vinylpyrrolidone.

13. The composition of claim 5, wherein the acrylonitrile polymer is polyacrylonitrile.

14. The composition of claim 5 dispersed in a solvent for polyacrylonitrile.

15. A filamentary shaped article comprised of a composition that is set forth in claim 5.

16. Method for the preparation of a dye-receptive, antistatic, synthetic, linear hydrophobic polymer composition which comprises immersing an aquagel of a fiber forming polymer of an ethylenically unsaturated monomeric material containing at least about percent by weight of acrylonitrile in the form of a shaped article into a dispersion of a graft copolymer of (a) between about 10 and 80 weight percent of at least one alkenyl group-containing organic sulfonic acid compound selected from the group consisting of those having the formulae:

all wherein X is selected from the group consisting of hydrogen, saturated aliphatic hydrocarbon radicals containing from 1 to 4 carbon atoms and alkali metals; Y is selected from the group consisting of hydrogen, chlorine and bromine; R is selected from the group consisting of methyl and ethyl; Z is selected from the group consisting of hydrogen and methyl; m is an integer from 0 to 2; n is an integer from 1 to 2; p is an integer from 0 to l; and r is an integer from 1 to 4; and (b) from about to 20 weight percent of a vinyl lactam polymer, until between about 2 to 20 percent by weight of said graft 'copolymer, basel on the weight of the resulting dry composition weight, is incorporated in said aquagel; and drying said graft copolymer-containing aquagel to convert it from the aquagel condition to a finished shaped article form.

17. The method of claim 16, wherein said arcrylonitrile polymer is polyacrylonitrile.

References Cited in the file of this patent UNITED STATES PATENTS MacGregor Mar. 11, 1947 Cameron et a1. Apr. 8, 1947 Cresswell et a1. Oct. 21, 1952 Ham June 30, 1953 Coover Feb. 21, 1956 10 FOREIGN PATENTS Great Britain Sept. 8, 1954 

5. COMPOSITION COMPRISING A MAJOR PROPORTION OF (A) A FIBER FORMING POLYMER OF AN ETHYLENICALLY UNSATURATED MONOMERIC MATERIAL CONTAINING AT LEAST ABOUT 80 PERCENT BY WEIGHT OF ACRYLONITRILE AND (B) A MINOR PROPORTION OF UP TO ABOUT 20 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE COMPOSITION, OF A GRAFT COPOLYMER OF (A) BETWEEN ABOUT 10 AND 80 WEIGHT PERCENT OF AT LEAST ONE ALKENYL GROUP-CONTAINING ORGANIC SULFONIC ACID COMPOUND SELECTED FROM THE GROUP CONSISTING OF THOSE HAVING THE FORMULAE: 